Block Explorers (with Insight API)
To keep your data safe, optional encryption is a must. First, your password is hardened using the famous Scrypt and PHC competition winner Argon2. Then your data is double-encrypted using ChaCha20 and the strongest AES mode, OCB. This is more than record high! (Scrypt license)
The blockchain must not be bloated with processed data. Instead, the data should be compressed as much as possible. LZMA is the leading compression algorithm with unbelievable efficiency.
It wouldn't be possible to design an amazing tool without a great cryptocurrency library! Its license and the licenses of the submodules can be found here
Fast checksum. License: here
Omni Layer's Class B
No, the limit is not 220 bytes per transaction. Tachikoma of BitcoinTalk has a good solution designed for OmniLayer.